Circuit boards, also referred to in German as circuit cards, “platins” or printed circuits (English: printed circuit board, PCB) are carriers of electronic components. They allow for mechanical fastening and electrical connection of the components placed on a circuit board in almost all electronic devices.
Such circuit boards for electrical modules must to some extent carry large currents for electric drives or the power supply for a device. One example is a circuit board for operating an inverter for an electrical refrigerating compressor.
To realize a great current-carrying capacity or current-load capacity and improved lateral heat transfer, it is known how to implement conductor tracks, also called conductor paths, on a circuit board with correspondingly great copper-layer thicknesses, e.g., in the 200 to 400 μm range through the use of so-called thick-copper technology.
Alternatively, a so-called inlay technique may be used, with which a solid copper part is pressed into and laminated with the circuit board.
Another option is to apply so-called busbars for carrying current and being arranged outside the circuit board.
Permissible amperages for specified conductor-track widths are provided, e.g., in Directive IPC2221, hereby incorporated herein by reference in its entirety.
The use of broad and thick layered copper conductor tracks, as well as busbars, entails high production and related costs as regards the printed circuit board to be manufactured.
Furthermore, the use of thick copper layers (thick-copper technology) gives rise to limitations in the resolution of conductor gaps (fine pitch). Thus, stricter regimentation must be observed during layout and production of a printed circuit board.
The main reason for the conductor cross-sections mentioned in the IPC2221 Directive is the self-heating of the conductor tracks caused by ohmic resistance. This self-heating can lead to the detachment of the copper interconnects of a carrier material (delamination), as well as the detachment of the individual support materials from one another and the destruction of the circuit board.